Scientists have created two new types of materials that can bend light the wrong way, creating the first step toward an invisibility cloaking device.
One approach uses a type of fishnet of metal layers to reverse the direction of light, while another uses tiny silver wires, both at the nanoscale level.
Both are so-called metamaterials — artificially engineered structures that have properties not seen in nature, such as negative refractive index.
The two teams were working separately under the direction of Xiang Zhang of the Nanoscale Science and Engineering Center at the University of California, Berkeley with U.S. government funding. One team reported its findings in the journal Science and the other in the journal Nature.
Each new material works to reverse light in limited wavelengths, so no one will be using them to hide buildings from satellites, said Jason Valentine, who worked on one of the projects.
“We are not actually cloaking anything,” Valentine said in a telephone interview. “I don’t think we have to worry about invisible people walking around any time soon. To be honest, we are just at the beginning of doing anything like that.”
Valentine’s team made a material that affects light near the visible spectrum, in a region used in fiber optics.
“In naturally occurring material, the index of refraction, a measure of how light bends in a medium, is positive,” he said.
“When you see a fish in the water, the fish will appear to be in front of the position it really is. Or if you put a stick in the water, the stick seems to bend away from you.”
These are illusions caused by the light bending when it moves between water and air.
NEGATIVE REFRACTION
The negative refraction achieved by the teams at Berkeley would be different.
“Instead of the fish appearing to be slightly ahead of where it is in the water, it would actually appear to be above the water’s surface,” Valentine said. “It’s kind of weird.”
For a metamaterial to produce negative refraction, it must have a structural array smaller than the wavelength of the electromagnetic radiation being used. This was done using microwaves in 2006 by David Smith of Duke University in North Carolina and John Pendry of Imperial College London.
Visible light is harder. Some groups managed it with very thin layers, virtually only one atom thick, but these materials were not practical to work with and absorbed a great deal of the light directed at it.
“What we have done is taken that material and made it much thicker,” Valentine said.
His team, whose work is reported in Nature, used stacked silver and metal dielectric layers stacked on top of each other and then punched through with holes. “We call it a fishnet,” Valentine said.The other team, reporting in Science, used an oxide template and grew silver nanowires inside porous aluminum oxide at tiny distances apart, smaller than the wavelength of visible light. This material refracts visible light.
Immediate applications might be superior optical devices, Valentine said — perhaps a microscope that could see a living virus.
“However, cloaking may be something that this material could be used for in the future,” he said. “You’d have to wrap whatever you wanted to cloak in the material. It would just send light around. By sending light around the object that is to be cloaked, you don’t see it.”
Maggie Fox (Washington Reuters)
Welp, that didn’t take too long. Around 1.5 years after it was first announced, Google has decided to “shut down its premium video service.” Nevertheless, the most intriguing aspect of the whole shebang is that customers who purchased DRM-laden files will reportedly no longer be able to view them once the Video Store closes up shop, and rather than refunding customers with, you know, real money, it sounds like Google plans to offer “fixed credit on the firm’s online payment system, Google Checkout, instead.” Interestingly, another report noted that the search giant would “provide refunds or online shopping vouchers for previously purchased videos that won’t be viewable,” so it looks like the final verdict remains to be seen.
While it’s far from the most spacious storage system we’ve seen, Netcom’s new eSATA-based NR5-4 system will accomodate four drives for up to to 3TB of storage in a RAID 5 configuration, something the company claims to be an industry first. If RAID 5 isn’t your thing, you can set things up in your choice of RAID 0 or 10 configurations as well, and you’ll be able to keep an eye on the goings on thanks to the unit’s backlit display. You’ll also, of course, get the requisite PCI host adapter, along with a one meter host cable, and a “comprehensive” one year warranty. Not surprisingly, the unit doesn’t exactly come cheap, with it boasting a near $2,000 price tag. If that’s not a deal-breaker, you can get your order in right now.
Snappy retinal scanners have been in the works for some time, and now Panasonic is apparently hoping to hasten those annoying ID checks by enabling security personnel to confirm the true identity of a person walking through in just “two seconds.” Additionally, this scanner does not require subjects to “focus on the equipment,” packs “multiple two-megapixel cameras,” and in case you couldn’t guess, is being marketed towards airports and high-security office buildings. No word just yet on when these may be rolled out for public use, but anything (well, almost) that speeds up our traveling is smiled upon by us.
The Yahoo! Search Marketing blog has just 
If you’re like most Windows XP users, you’re perfectly willing to wait for Windows Vista Service Pack 13 to be released before upgrading. Well, there’s good news. If you can hold out for three more years, you can skip over Vista entirely and get the next version of Microsoft’s operating system, which the company is internally referring to as “Windows 7.”
Recent Comments